In Risk of Rain, time = difficulty. The longer you play the harder it gets, do you tear through the levels as fast as you can or do you spend time collecting some of the many ability granting artifacts? With randomly generated levels, giant bosses and just one life. How far will you go?

Hey there, I've been playing the alpha, and now more recently, the demo, for awhile and I have a few suggestions I think will improve the game.
1) Randomly generated maps. I don't understand why they aren't already. Do you guys have a specific reason the maps are all static? As it says on the front page: "The three main goals for our game are simple: 1. Design a game that is randomly generated every play-through, to keep replayability high and fresh." Based on this design philosophy, it seems to make sense that the levels should be randomized. I think the game has a lot to gain from randomizing the world.

2) A minimap of some kind. It would be very cool if this was an item pick-up, actually. However, the caveat is that the mini-map is next to worthless if the levels remain static (as you can just memorize the layouts).

3) It would also be very helpful if the "non-stackable" items only dropped once per game. Like the Fireman's boots, or the Brilliant Behemoth, Gasoline, or the Hit List, for example (which, as far as I can tell, don't help when stacked). I would allow the usable items to drop more than once, however, as you never know if players will swap them out. It also means that "junk" can still drop after you've collected all of the awesome items, which can add disappointment to drops. Or, in other words, it could add excitement to non-junk drops.
4) I think the descriptions of items should all be slightly more sneaky, like the Ukulele. It's fun to discover what the items do simply by using them. It might be worth considering to add a description to the item page after you've collected it like 3 - 5 times or so. Before that, the item page could just read "Unknown properties. Not enough data to run analysis. Collect more." Or, instead of that, a "shipping log" could randomly drop when you pick up an item, which grants access to the item's description.

5) Level up suggestions:

STATS. Right now, it feels kinda unimportant to level up, and it's very ambiguous what happens during a level up. I realize it increases your damage and health, but it would feel better if it said "level up! +5 DMG and + 50 HP" or something. You could even add a "ultimate" skill with a long cooldown, like League of Legends, that opens up when you hit level 6 or 10 or something to make levels feel much more important.

Right now, rate of level ups fall off a cliff when you hit like 10 - 12. You're cruising along, gaining level ups frequently, then suddenly, you're not. It's weird. I think there should be a more gentle curve to help sort this out. Naturally, you'd need balance the stats you get and whatnot to be around the appropriate times, but I think it would help make the game feel less "brick wall-y" at times. Meaning that currently, you need items, and items only, otherwise you're toast. Levels should matter. They need to feel really awesome, just like the items do. I get the impression that they're just a side-thought, and don't effect my play in any real way.
6) A "final level," with an epic boss (naturally), so you can beat the game. I know this is already being worked on, I just am mentioning it because it's very important. Players need an objective.
7) Finally, and most importantly, this game needs hundreds upon hundreds of unlockables (literally). Just look at the Binding of Issac. People are STILL playing it, and have been for hundreds of hours. Why? One reason is that the game has some serious and awesome unlockables. If Risk of Rain has TONS of stuff to collect by release, it'll match BoI's replayablity. I'm talking about additional items. Additional characters. Additional normal-level bosses. Additional final bosses. Additional maps. Additional character skins. Additional enemies. Additional secrets (the more jam-packed it is with Easter-eggs and goodies, the better it'll be). Additional music. Additional weapons. Additional everything. The game should simply keep expanding as you keep playing.

Anyway, that's all I can come up with at the moment. Thanks for making this really fun game! I tossed you guys a few dollars on the kickstarter, hope it helps.